On-chip magnon polaron generation in mode-matched cavity magnomechanics

TL;DR

This paper demonstrates on-chip generation of magnon polarons through a mode-matched magnomechanical system, significantly improving magnon-phonon coupling by optimizing spatial mode overlap for potential phononic device applications.

Contribution

The study introduces a novel on-chip configuration with a thin piezoelectric film on a thick magnetic layer, enabling strong magnon-phonon coupling over a large mode volume.

Findings

Successful generation of magnon polarons with distinct avoided crossing spectra

Enhanced spatial mode overlap in the on-chip system

Potential for coherent magnon-phonon conversion in phononic devices

Abstract

Generation of magnon polarons, which are hybridized states resulting from strong magnon-phonon coupling, is a key to enabling coherent manipulation in acoustic and spintronic devices. However, the conventional device configuration, a magnetic thin film on a thick piezoelectric layer, often has difficulty achieving a large magnon-phonon coupling due to a very small spatial mode overlap. Here, we demonstrate generation of magnon polarons by using a mode-matched on-chip magnomechanical system. A configuration with a thin piezoelectric film on a magnetic layer several micrometers thick was found to sustain deeply distributed magnon modes that enable magnetoelastic coupling to phonons over almost the entire mode volume. The enhanced spatial mode overlap generated magnon polarons whose spectra showed distinct avoided crossing. This magnomechanical system will facilitate utilization of coherent magnon-phonon conversion and their hybrid states in functional phononic devices.